LIVIVO - The Search Portal for Life Sciences

zur deutschen Oberfläche wechseln
Advanced search

Search results

Result 1 - 10 of total 818

Search options

  1. Article ; Online: Logistic growth modelling of COVID-19 proliferation in China and its international implications.

    Shen, Christopher Y

    International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases

    2020  Volume 96, Page(s) 582–589

    Abstract: Objective: As the coronavirus disease 2019 (COVID-19) pandemic continues to proliferate globally, this paper shares the findings of modelling the outbreak in China at both provincial and national levels. This paper examines the applicability of the ... ...

    Abstract Objective: As the coronavirus disease 2019 (COVID-19) pandemic continues to proliferate globally, this paper shares the findings of modelling the outbreak in China at both provincial and national levels. This paper examines the applicability of the logistic growth model, with implications for the study of the COVID-19 pandemic and other infectious diseases.
    Methods: An NLS (Non-Linear Least Squares) method was employed to estimate the parameters of a differentiated logistic growth function using new daily COVID-19 cases in multiple regions in China and in other selected countries. The estimation was based upon training data from January 20, 2020 to March 13, 2020. A restriction test was subsequently implemented to examine whether a designated parameter was identical among regions or countries, and the diagnosis of residuals was also conducted. The model's goodness of fit was checked using testing data from March 14, 2020 to April 18, 2020.
    Results: The model presented in this paper fitted time-series data exceedingly well for the whole of China, its eleven selected provinces and municipalities, and two other countries - South Korea and Iran - and provided estimates of key parameters. This study rejected the null hypothesis that the growth rates of outbreaks were the same among ten selected non-Hubei provinces in China, as well as between South Korea and Iran. The study found that the model did not provide reliable estimates for countries that were in the early stages of outbreaks. Furthermore, this study concured that the R
    Conclusions: The findings suggest that there is potential for this model to contribute to better public health policy in combatting COVID-19. The model does so by providing a simple logistic framework for retrospectively analyzing outbreaks in regions that have already experienced a maximal proliferation in cases. Based upon statistical findings, this study also outlines certain challenges in modelling and their implications for the results.
    MeSH term(s) Betacoronavirus ; COVID-19 ; China/epidemiology ; Coronavirus Infections/epidemiology ; Humans ; Iran/epidemiology ; Logistic Models ; Pandemics ; Pneumonia, Viral/epidemiology ; Republic of Korea/epidemiology ; Retrospective Studies ; SARS-CoV-2
    Keywords covid19
    Language English
    Publishing date 2020-05-04
    Publishing country Canada
    Document type Journal Article
    ZDB-ID 1331197-9
    ISSN 1878-3511 ; 1201-9712
    ISSN (online) 1878-3511
    ISSN 1201-9712
    DOI 10.1016/j.ijid.2020.04.085
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  2. Article ; Online: Logistic growth modelling of COVID-19 proliferation in China and its international implications

    Shen, Christopher Y.

    International Journal of Infectious Diseases

    2020  Volume 96, Page(s) 582–589

    Keywords Microbiology (medical) ; Infectious Diseases ; General Medicine ; covid19
    Language English
    Publisher Elsevier BV
    Publishing country us
    Document type Article ; Online
    ZDB-ID 1331197-9
    ISSN 1878-3511 ; 1201-9712
    ISSN (online) 1878-3511
    ISSN 1201-9712
    DOI 10.1016/j.ijid.2020.04.085
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    More links

    Kategorien

  3. Article ; Online: Logistic growth modelling of COVID-19 proliferation in China and its international implications

    Christopher Y. Shen

    International Journal of Infectious Diseases, Vol 96, Iss , Pp 582-

    2020  Volume 589

    Abstract: Objective: As the coronavirus disease 2019 (COVID-19) pandemic continues to proliferate globally, this paper shares the findings of modelling the outbreak in China at both provincial and national levels. This paper examines the applicability of the ... ...

    Abstract Objective: As the coronavirus disease 2019 (COVID-19) pandemic continues to proliferate globally, this paper shares the findings of modelling the outbreak in China at both provincial and national levels. This paper examines the applicability of the logistic growth model, with implications for the study of the COVID-19 pandemic and other infectious diseases. Methods: An NLS (Non-Linear Least Squares) method was employed to estimate the parameters of a differentiated logistic growth function using new daily COVID-19 cases in multiple regions in China and in other selected countries. The estimation was based upon training data from January 20, 2020 to March 13, 2020. A restriction test was subsequently implemented to examine whether a designated parameter was identical among regions or countries, and the diagnosis of residuals was also conducted. The model's goodness of fit was checked using testing data from March 14, 2020 to April 18, 2020. Results: The model presented in this paper fitted time-series data exceedingly well for the whole of China, its eleven selected provinces and municipalities, and two other countries - South Korea and Iran - and provided estimates of key parameters. This study rejected the null hypothesis that the growth rates of outbreaks were the same among ten selected non-Hubei provinces in China, as well as between South Korea and Iran. The study found that the model did not provide reliable estimates for countries that were in the early stages of outbreaks. Furthermore, this study concured that the R2 values might vary and mislead when compared between different portions of the same non-linear curve. In addition, the study identified the existence of heteroskedasticity and positive serial correlation within residuals in some provinces and countries. Conclusions: The findings suggest that there is potential for this model to contribute to better public health policy in combatting COVID-19. The model does so by providing a simple logistic framework for retrospectively analyzing outbreaks in regions that have already experienced a maximal proliferation in cases. Based upon statistical findings, this study also outlines certain challenges in modelling and their implications for the results.
    Keywords COVID-19 ; Logistic growth model ; Non-linear least squares ; China ; Infectious and parasitic diseases ; RC109-216 ; covid19
    Subject code 950
    Language English
    Publishing date 2020-07-01T00:00:00Z
    Publisher Elsevier
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    More links

    Kategorien

  4. Article: Logistic growth modelling of COVID-19 proliferation in China and its international implications

    Shen, Christopher Y

    Int J Infect Dis

    Abstract: OBJECTIVE: As the coronavirus disease 2019 (COVID-19) pandemic continues to proliferate globally, this paper shares the findings of modelling the outbreak in China at both provincial and national levels. This paper examines the applicability of the ... ...

    Abstract OBJECTIVE: As the coronavirus disease 2019 (COVID-19) pandemic continues to proliferate globally, this paper shares the findings of modelling the outbreak in China at both provincial and national levels. This paper examines the applicability of the logistic growth model, with implications for the study of the COVID-19 pandemic and other infectious diseases. METHODS: An NLS (Non-Linear Least Squares) method was employed to estimate the parameters of a differentiated logistic growth function using new daily COVID-19 cases in multiple regions in China and in other selected countries. The estimation was based upon training data from January 20, 2020 to March 13, 2020. A restriction test was subsequently implemented to examine whether a designated parameter was identical among regions or countries, and the diagnosis of residuals was also conducted. The model's goodness of fit was checked using testing data from March 14, 2020 to April 18, 2020. RESULTS: The model presented in this paper fitted time-series data exceedingly well for the whole of China, its eleven selected provinces and municipalities, and two other countries - South Korea and Iran - and provided estimates of key parameters. This study rejected the null hypothesis that the growth rates of outbreaks were the same among ten selected non-Hubei provinces in China, as well as between South Korea and Iran. The study found that the model did not provide reliable estimates for countries that were in the early stages of outbreaks. Furthermore, this study concured that the R2 values might vary and mislead when compared between different portions of the same non-linear curve. In addition, the study identified the existence of heteroskedasticity and positive serial correlation within residuals in some provinces and countries. CONCLUSIONS: The findings suggest that there is potential for this model to contribute to better public health policy in combatting COVID-19. The model does so by providing a simple logistic framework for retrospectively analyzing outbreaks in regions that have already experienced a maximal proliferation in cases. Based upon statistical findings, this study also outlines certain challenges in modelling and their implications for the results.
    Keywords covid19
    Publisher WHO
    Document type Article
    Note WHO #Covidence: #625889
    Database COVID19

    Kategorien

  5. Article ; Online: Differential sex-dependent susceptibility to diastolic dysfunction and arrhythmia in cardiomyocytes from obese diabetic HFpEF model.

    Mira Hernandez, Juliana / Shen, Erin Y / Ko, Christopher Y / Hourani, Zaynab / Spencer, Emily R / Smoliarchuk, Daria / Bossuyt, Julie / Granzier, Henk / Bers, Donald M / Hegyi, Bence

    Cardiovascular research

    2024  

    Abstract: Aim: Sex-differences in heart failure with preserved ejection fraction (HFpEF) are important, but key mechanisms involved are incompletely understood. While animal models can inform about sex-dependent cellular and molecular changes, many previous ... ...

    Abstract Aim: Sex-differences in heart failure with preserved ejection fraction (HFpEF) are important, but key mechanisms involved are incompletely understood. While animal models can inform about sex-dependent cellular and molecular changes, many previous preclinical HFpEF models have failed to recapitulate sex-dependent characteristics of human HFpEF. We tested for sex-differences in HFpEF using a two-hit mouse model (leptin receptor-deficient db/db mice plus aldosterone infusion for 4 weeks; db/db+Aldo).
    Methods and results: We performed echocardiography, electrophysiology, intracellular Ca2+ imaging, and protein analysis. Female HFpEF mice exhibited more severe diastolic dysfunction in line with increased titin N2B isoform expression and PEVK element phosphorylation, and reduced troponin-I phosphorylation. Female HFpEF mice had lower BNP levels than males despite similar comorbidity burden (obesity, diabetes) and cardiac hypertrophy in both sexes. Male HFpEF mice were more susceptible to cardiac alternans. Male HFpEF cardiomyocytes (versus female) exhibited higher diastolic [Ca2+], slower Ca2+ transient decay, reduced L-type Ca2+ current, more pronounced enhancement of the late Na+ current, and increased short-term variability of action potential duration (APD). However, male and female HFpEF myocytes showed similar downregulation of inward rectifier and transient outward K+ currents, APD prolongation, and frequency of delayed afterdepolarizations. Inhibition of Ca2+/calmodulin-dependent protein kinase II (CaMKII) reversed all pathological APD changes in HFpEF in both sexes, and empagliflozin pretreatment mimicked these effects of CaMKII inhibition. Vericiguat had only slight benefits, and these effects were larger in HFpEF females.
    Conclusion: We conclude that the db/db+Aldo preclinical HFpEF murine model recapitulates key sex-specific mechanisms in HFpEF and provides mechanistic insights into impaired excitation-contraction coupling and sex-dependent differential arrhythmia susceptibility in HFpEF with potential therapeutic implications. In male HFpEF myocytes, altered Ca2+ handling and electrophysiology aligned with diastolic dysfunction and arrhythmias, while worse diastolic dysfunction in females may depend more on altered myofilaments properties.
    Language English
    Publishing date 2024-04-26
    Publishing country England
    Document type Journal Article
    ZDB-ID 80340-6
    ISSN 1755-3245 ; 0008-6363
    ISSN (online) 1755-3245
    ISSN 0008-6363
    DOI 10.1093/cvr/cvae070
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  6. Article ; Online: Nitrosylation of cardiac CaMKII at Cys290 mediates mechanical afterload-induced increases in Ca

    Alim, Chidera C / Ko, Christopher Y / Mira Hernandez, Juliana / Shen, Erin Y / Baidar, Sonya / Chen-Izu, Ye / Bers, Donald M / Bossuyt, Julie

    The Journal of physiology

    2022  Volume 600, Issue 22, Page(s) 4865–4879

    Abstract: Cardiac mechanical afterload induces an intrinsic autoregulatory increase in myocyte ... ...

    Abstract Cardiac mechanical afterload induces an intrinsic autoregulatory increase in myocyte Ca
    MeSH term(s) Mice ; Animals ; Calcium-Calmodulin-Dependent Protein Kinase Type 2/metabolism ; Sarcoplasmic Reticulum/metabolism ; Myocytes, Cardiac/metabolism ; Ryanodine Receptor Calcium Release Channel/metabolism ; Calcium/metabolism ; Calcium Signaling/physiology
    Chemical Substances Calcium-Calmodulin-Dependent Protein Kinase Type 2 (EC 2.7.11.17) ; Ryanodine Receptor Calcium Release Channel ; Calcium (SY7Q814VUP)
    Language English
    Publishing date 2022-10-30
    Publishing country England
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 3115-x
    ISSN 1469-7793 ; 0022-3751
    ISSN (online) 1469-7793
    ISSN 0022-3751
    DOI 10.1113/JP283427
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  7. Article ; Online: Vaginal Lubrication and Pressure Increase Induced by Pudendal Nerve Stimulation in Cats.

    Chen, Jialiang / Zhong, Yihua / Wang, Jicheng / Shen, Bing / Shen, Zhijun / Beckel, Jonathan / de Groat, William / Chermansky, Christopher / Tai, Changfeng

    The journal of sexual medicine

    2022  Volume 19, Issue 10, Page(s) 1517–1523

    Abstract: ... and induce increases in vaginal pressure. Chen J, Zhong Y, Wang J, et al. Vaginal Lubrication and ...

    Abstract Background: Vaginal lubrication and contractions are among the top difficulties affecting sexual intercourse in women after spinal cord injury.
    Aim: This study aimed at determining if pudendal nerve stimulation (PNS) can improve vaginal lubrication and induce increases in vaginal pressure.
    Methods: In anesthetized cats, a small piece of cotton was inserted into the vagina for 10 minutes with or without PNS to measure vaginal wetness by the weight increase of the vaginal cotton. Then, a small balloon catheter was inserted into the vagina to measure the pressure increase induced by PNS. Intensity response of the vagina to PNS (30 Hz, 0.2 ms, 5 seconds) was determined at 1-4 times of intensity threshold (T) for PNS to induce an observable vaginal pressure increase. Frequency response was determined at 2T intensity in a range of PNS frequencies (5-50 Hz). Finally, fatigue in vaginal pressure was determined by applying PNS (30 Hz, 2T) either continuously or intermittently (5 seconds on and 5 seconds off) for 4 minutes.
    Outcomes: The effectiveness of PNS in increasing vaginal wetness and pressure is evaluated.
    Results: PNS significantly (P = .0327) increased the measurement of vaginal wetness from 15.8 ± 3.8 mg during control without stimulation to 32.4 ± 4.7 mg after stimulation. Vaginal pressure increased as PNS intensity or frequency increased. PNS (30 Hz, 2T) induced vaginal pressure increase ≥80% of the maximal response. Intermittent PNS induced significantly (P = .0354) smaller fatigue (45.6 ± 3.7%) in vaginal pressure than continuous PNS (69.1 ± 3.0%) during the 4-minute stimulation.
    Clinical translation: This study raises the possibility of developing a novel pudendal neuromodulation device to improve female sexual function after spinal cord injury.
    Strengths & limitations: This study provides preclinical data supporting the development of a novel pudendal neuromodulation device. The limitation includes the lack of chemical analysis of the vaginal secretion.
    Conclusion: PNS can improve vaginal lubrication and induce increases in vaginal pressure. Chen J, Zhong Y, Wang J, et al. Vaginal Lubrication and Pressure Increase Induced by Pudendal Nerve Stimulation in Cats. J Sex Med 2022;19:1517-1523.
    MeSH term(s) Animals ; Cats ; Electric Stimulation ; Female ; Lubrication ; Muscle Fatigue ; Pressure ; Pudendal Nerve/physiology ; Vagina/physiology
    Language English
    Publishing date 2022-08-31
    Publishing country Netherlands
    Document type Journal Article ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 2251959-2
    ISSN 1743-6109 ; 1743-6095
    ISSN (online) 1743-6109
    ISSN 1743-6095
    DOI 10.1016/j.jsxm.2022.07.012
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  8. Article ; Online: Cardiac Protein Kinase D1 ablation alters the myocytes β-adrenergic response.

    Mira Hernandez, Juliana / Ko, Christopher Y / Mandel, Avery R / Shen, Erin Y / Baidar, Sonya / Christensen, Ashley R / Hellgren, Kim / Morotti, Stefano / Martin, Jody L / Hegyi, Bence / Bossuyt, Julie / Bers, Donald M

    Journal of molecular and cellular cardiology

    2023  Volume 180, Page(s) 33–43

    Abstract: β-adrenergic (β-AR) signaling is essential for the adaptation of the heart to exercise and stress. Chronic stress leads to the activation of ... ...

    Abstract β-adrenergic (β-AR) signaling is essential for the adaptation of the heart to exercise and stress. Chronic stress leads to the activation of Ca
    MeSH term(s) Animals ; Mice ; Adrenergic Agents/pharmacology ; Adrenergic beta-Agonists/pharmacology ; Adrenergic beta-Agonists/metabolism ; Calcium/metabolism ; Calcium Signaling ; Calcium-Calmodulin-Dependent Protein Kinase Type 2/metabolism ; Mice, Knockout ; Myocytes, Cardiac/metabolism ; Phosphorylation ; Ryanodine Receptor Calcium Release Channel/metabolism ; Sarcoplasmic Reticulum/metabolism ; Protein Kinase C/genetics
    Chemical Substances Adrenergic Agents ; Adrenergic beta-Agonists ; Calcium (SY7Q814VUP) ; Calcium-Calmodulin-Dependent Protein Kinase Type 2 (EC 2.7.11.17) ; Ryanodine Receptor Calcium Release Channel ; Protein Kinase C (EC 2.7.11.13)
    Language English
    Publishing date 2023-05-04
    Publishing country England
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 80157-4
    ISSN 1095-8584 ; 0022-2828
    ISSN (online) 1095-8584
    ISSN 0022-2828
    DOI 10.1016/j.yjmcc.2023.05.001
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  9. Article ; Online: Dysregulation of CD4

    He, Jun Yan / Kim, Yang-Joon / Mennillo, Elvira / Rusu, Iulia / Bain, Jared / Rao, Arjun A / Andersen, Christopher / Law, Karen / Yang, Hai / Tsui, Jessica / Shen, Alan / Davidson, Brittany / Kushnoor, Divyashree / Shi, Yimin / Fan, Frances / Cheung, Alexander / Zhang, Li / Fong, Lawrence / Combes, Alexis J /
    Pisco, Angela O / Kattah, Michael G / Oh, David Y

    Journal for immunotherapy of cancer

    2024  Volume 12, Issue 4

    Abstract: Background: Colitis caused by checkpoint inhibitors (CPI) is frequent and is treated with empiric steroids, but CPI colitis mechanisms in steroid-experienced or refractory disease are unclear.: Methods: Using colon biopsies and blood from ... ...

    Abstract Background: Colitis caused by checkpoint inhibitors (CPI) is frequent and is treated with empiric steroids, but CPI colitis mechanisms in steroid-experienced or refractory disease are unclear.
    Methods: Using colon biopsies and blood from predominantly steroid-experienced CPI colitis patients, we performed multiplexed single-cell transcriptomics and proteomics to nominate contributing populations.
    Results: CPI colitis biopsies showed enrichment of CD4
    Conclusions: These findings nominate CD4
    MeSH term(s) Humans ; CD8-Positive T-Lymphocytes ; Endothelial Cells ; Tumor Necrosis Factor Inhibitors ; Colitis/chemically induced ; Colitis/drug therapy ; CD4-Positive T-Lymphocytes ; Steroids/pharmacology ; Steroids/therapeutic use ; Stromal Cells
    Chemical Substances Tumor Necrosis Factor Inhibitors ; Steroids
    Language English
    Publishing date 2024-04-19
    Publishing country England
    Document type Journal Article
    ZDB-ID 2719863-7
    ISSN 2051-1426 ; 2051-1426
    ISSN (online) 2051-1426
    ISSN 2051-1426
    DOI 10.1136/jitc-2023-008628
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  10. Article ; Online: Metagenomic insights into the microbial communities of inert and oligotrophic outdoor pier surfaces of a coastal city.

    Tong, Xinzhao / Leung, Marcus H Y / Shen, Zhiyong / Lee, Justin Y Y / Mason, Christopher E / Lee, Patrick K H

    Microbiome

    2021  Volume 9, Issue 1, Page(s) 213

    Abstract: Background: Studies of the microbiomes on surfaces in built environment have largely focused on indoor spaces, while outdoor spaces have received far less attention. Piers are engineered infrastructures commonly found in coastal areas, and due to their ... ...

    Abstract Background: Studies of the microbiomes on surfaces in built environment have largely focused on indoor spaces, while outdoor spaces have received far less attention. Piers are engineered infrastructures commonly found in coastal areas, and due to their unique locations at the interface between terrestrial and aquatic ecosystems, pier surfaces are likely to harbor interesting microbiology. In this study, the microbiomes on the metal and concrete surfaces at nine piers located along the coastline of Hong Kong were investigated by metagenomic sequencing. The roles played by different physical attributes and environmental factors in shaping the taxonomic composition and functional traits of the pier surface microbiomes were determined. Metagenome-assembled genomes were reconstructed and their putative biosynthetic gene clusters were characterized in detail.
    Results: Surface material was found to be the strongest factor in structuring the taxonomic and functional compositions of the pier surface microbiomes. Corrosion-related bacteria were significantly enriched on metal surfaces, consistent with the pitting corrosion observed. The differential enrichment of taxa mediating biodegradation suggests differences between the metal and concrete surfaces in terms of specific xenobiotics being potentially degraded. Genome-centric analysis detected the presence of many novel species, with the majority of them belonging to the phylum Proteobacteria. Genomic characterization showed that the potential metabolic functions and secondary biosynthetic capacity were largely correlated with taxonomy, rather than surface attributes and geography.
    Conclusions: Pier surfaces are a rich reservoir of abundant novel bacterial species. Members of the surface microbial communities use different mechanisms to counter the stresses under oligotrophic conditions. A better understanding of the outdoor surface microbiomes located in different environments should enhance the ability to maintain outdoor surfaces of infrastructures. Video Abstract.
    MeSH term(s) Bacteria/genetics ; Metagenome ; Metagenomics ; Microbiota/genetics ; Proteobacteria/genetics
    Language English
    Publishing date 2021-11-02
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Video-Audio Media
    ZDB-ID 2697425-3
    ISSN 2049-2618 ; 2049-2618
    ISSN (online) 2049-2618
    ISSN 2049-2618
    DOI 10.1186/s40168-021-01166-y
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

To top